Scarifier tooth



May 29, 1934. c. A. RUSSELL ET AL SCARIFIER TOOTH Filed May 22. 1931 ,Zhren far: Cfiar/es A Rad; el/

Carroll IV. h/a

jffarn ey Patented May 29, 1934 I SCARIFIER TOOTH Charles A. Russell and Carroll M. Walker, Los

Angeles, Calif" Los Angeles, Calif.,

assignors to Mills Alloys, Inc., a

a corporation of Delaware Application May 22, 1931, Serial No. 539,284

3 Claims.

This invention relates to scarifler teeth, and is a continuation in part of our copending application, Serial No. 472,879, filed August 4, 1930.

Scarifler teeth are quite generally arranged in series on a support and operated by means of horses or tractors to break up or cut the earths strata. These teeth are subjected to extremely rough usage and must of necessity be capable of withstanding great pressure and wear. We have found that by the use of tungsten carbide, or tungsten carbide containing other metals, as a cutting edge and surface, a product is produced which will resist the rough usage and abrading action for an indeterminate period of time. Preferably, the tungsten carbide should be in the form of granules or particles which are bonded into a conglomerate mass by a material of a lesser degree of hardness such as mild steel. If desired, large granules or chunks of tungsten carbide can be interspersed throughout the conglomerate mass in order to more effectively scarify hard' arth or cement crusts.

It is an object of this invention to provide a scarifier blade having a cutting edge and surface formed of a wear resisting material such as tungsten carbide in granular form.

It is a further object of this invention to provide a tungsten carbide cutting rib for a scarifier tooth formed of a conglomerate mass of tungsten carbide particles and a binder, in which large granules of tungsten carbide are interspersed in desired places.

It is a further object of this invention to provide a scarifier tooth formed of a tough, nonfatigueabie metallic material which serves as a backing for the cutting rib and which is capable of withstanding intense heat without impairing its hardness or temper.

Our invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of one embodiment of our invention. For this purpose we have shown a form in the drawing accompanying and forming part of the present specification. We shall now proceed to describe this form in detail, which illustrates the general principles of our invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of our invention is best defined by the appended claims.

Referring to the drawing:

Figure l is a side elevational view of a scarifying tooth embodying our invention;

Fig. 2 is a transverse section taken along plane 2-2 of Fig. 1;

Fig. 3 is a transverse section of a modified form of scarifying tooth embodying our invention.

The scarifying tooth shown in Fig. 1' comprises an elongated metallic supporting member or backing 10 having a square cross-section. The lower end of the backing is tapered as at 11 to'provide a point 12 in order to facilitate the scarifying action. The backing is preferably formed of a tough, non-fatigueable metallic material, such as can readily withstand intense heat without impairment to its hardness or temper. Any suitable material can be used for this purpose, although preferably we employ a chrome vanadium steel due to its desirable physical characteristics.

The backing member 10 out portion or groove 13 at the lower portion thereof and along one edge. The groove should 7 preferably be formed with a round or substantially rounded bottom in order to prevent the formation of cracks or ruptures in the backing 10 when the tungsten carbide particles are inserted in the groove in a manner to be described. 30 This groove may be formed in any desirable manner, such as by casting, rolling, forging or machining.

To manufacture tungsten carbide in long preformed sticks, and to secure them in a precut opening or groove is not commercially feasible, due to the extreme brittle characteristics of the material. It is therefore necessary to fill up the cut out portion or groove 13 with tungsten carbide particles or granules of varying size to form an insert or rib l4.

Tungsten carbide granules of a size not smaller than that which will pass through a sixty mesh screen, or larger than that which can pass through a sixteen mesh screen, are mechanically mixed with iron or an iron alloy, nickel, cobalt, or other metals or alloys of the iron group. Preferably a mechanical mixture is formed which contains granules varying between a thirty and sixteen mesh; that is, granules of a size not smaller than that which will barely pass through a thirty mesh screen, or larger than that which can pass through a sixteen mesh screen.

This mechanical mixture comprising the desired size of granules is placed in the cut-out portion or groove 13, and secured therein by means of a welding action brought about by means of an acetylene torch, or any other suitable source of heat. The heat issuing from the torch, acts on the metal or other alloy other than tungsten is formed with a cutcarbide to melt the same and cause it to act as a carrier or float tor the tungsten carbide granules. Upon cooling the metal or alloy other than tungsten carbide is adhesively secured to the walls of the groove, and the tungsten carbide granules, are maintained as such, by the melted and resolidified metal or alloy. Experimentation has shown that the metal or alloy to be capable of acting as a pool for the tungsten carbide, should not exceed 10% by weight of the mixture, in order to obtain the best results; however, this percentage is not to be construed as limiting.

The welding action hereinabove described may be performed a sufllcient number of times to produce the rib 14 of wear resisting material. This invention is not to be limited to the specific means of forming the rib, as any other desirable means may be used with equal advantage.

In actual practice, the scarifier tooth is dragged through the earth's crust with the cutting rib 14 first exposed or subjected to the earth. Due to the granular particles of tungsten carbide, the cutting is greatly facilitated, and a tooth is provided which is capable of use for an indeterminate period of time. The particles of tungsten carbide are exposed as cutting elements when a portion of the bonding medium has worn away. As the sides of the backing 10 adjacent the groove 13 are also subjected to the abrasive action of the earth's crust, it is desirable to cover the exposed faces with thin layers 15 and 16 of a material similar to the rib 14. In this manner, the life of the tooth is greatlyprolonged.

If desired, lumps or granules 17 of tungsten carbide can be inserted in the cutting edge at spaced intervals. These lumps can be of any size larger than the largest granules making up the mechanical mixture, although we preferably utilize granules in the order of one eighth to a half inch in diameter. Thegranules 1'7 greatly increase the efiiciency of the tooth due to the increase in cutting power resulting from the use of these larger granules.

In Fig. 3 we show a modification in the position of the groove 13 shown in Fig. 2. In this instance, a groove 18 is formed in one side 01' the backing 10 and filled with a rib 19 similar to rib 14 in a manner already described. Additional life can'be added to the sacrifler tooth by the addition of layers 20 and 21 adjacent the groove 18, of a material similar to rib 19. It is apparent from the foregoing, that if desired, a multiplicity of the sides of the backing 10 can be formed with a rib and layers of wear resisting material.

' Although we have shown and described a scarifier tooth having a square cross-section, ominvention is equally applicable to teeth having a triangular, rectangular, or other geometrical cross-section.

We claim:

1. A tooth adapted for use in road machinery and subjected to longitudinal wear, said tooth having a groove in one edge extending in a longitudinal direction, and wearing material in said groove, comprising particles of tungsten carbide and a binder, said particles and the binder being integrally joined to the tooth by fusion, and some of said particles being materially larger than the others and located immediately at the surface. of the tooth.

2. A tcoth adapted for use in road machinery and subjected to longitudinal wear, said tooth having a groove in one edge extending in a longitudinal direction, wearing material in said groove, comprising particles of tungsten carbide and a binder, said particles and the binder being integrally joined to the tooth by fusion, and some of said particles being materially larger than the others and located immediately at the surface of the tooth, and a layer of wearing material on those faces of the tooth that are adjacent the groove, said wearing layer being comprised of tungsten carbide particles and a binder integrally joined by fusion to the tooth.

3. The combination as set forth in claim 1, in which the tooth is made from chrome vanadium steel, and the binder is a composition of the iron group having yielding characteristics.

CHARLES A. RUSSELL.

CARRQLL M. WAW R. 

